With the development of mobile communications, mobile terminals have been widely used around the world. Vigorous competitions exist among different mobile communication operators in order to seize the markets. At present, in order to enlarge market shares, operators usually purchase a large number of mobile terminals from mobile terminal manufacturers in a centralized way, and require the purchased mobile terminals to be locked to the networks operated by them. Then, the operators bind the purchased mobile terminals to a very favorable set and sell them with the mobile terminals marked at junk prices (which is referred to as subsidies), in a bid to quickly increase their market shares.
The foresaid mobile terminals are all network-locked mobile terminals, so they cannot work normally and find a network unless a SIM (Subscriber Identity Module) card from a specific operator is inserted. However, an Unlock SimCard that can crack network-locked mobile terminals has been developed. The Unlock SimCard is similar to the SIM card and can crack almost all network-locked mobile terminals of predominant brands in the market. The Unlock SimCard paralyzes the network-locked function of mobile terminals, brings the huge amount of subsidies made by operators to naught, affects the market shares of the operators and seriously impairs their interests. To tackle this problem, operators urgently need an anti-crack method for network-locked mobile terminals to protect their interests from being infringed.